This application is to provide an internal combustion engine system for enhancing the net thermal efficiency of the conventional internal combustion engine, in particular to provide an internal combustion engine system for a four-stroke diesel engine. In the above U.S. patent application No. 438,647 disclosed by Mr. C. W. Nam, now U.S. Pat. No. 4,531,480, the piston power transmission apparatus is constructed in accordance with Pascal's Law which states that a confined fluid transmits externally applied pressure uniformly in all directions without change in magnitude. Substantially, the piston power transmission apparatus in the cited reference comprises an upper cylinder block and a lower cylinder block provided wtih a top piston and a bottom piston individually. The space between the top piston and bottom piston is filed with compressed oil. Also an upper cylinder block is divided into an internal chamber and an external chamber by a vertical wall, whereby the pressure of the upper cylinder, which is equal to that of the general cylinder produced by the gas explosion during the power stroke, is transmitted through the fluid oil to the bottom piston so that said pressure is multiplied by the cross-sectional area ratio between the top piston and the bottom piston. But such a piston power transmission apparatus has disadvantages and problems. For example, as the upper piston is reciprocated at a high velocity along the vertical wall in the upper cylinder block, the temperature of the fluid oil therein is greatly increased due to the oil pumping action and engine combustion heat notwithstanding the cooling action by the cooling water jacket mounted in the upper cylinder block. Also, even though the vertical wall and the upper piston are accurately casted and the piston ring, oil ring and seal ring are fitted into the ring groove of the upper piston to prevent the oil from leaking into the combustion chamber, a small quantity of fluid oil is introduced into the combustion chamber, thereby resulting in incomplete combustion and air pollution.
Therefore, this invention is constructed to solve the above problems and to overcome the above disadvantages. In other words, this invention is designed to prevent fluid oil leakage, and to reduce a rise in oil temperature during piston reciprocation. Also, this invention is provided with a wasteheat circulating system which utilizes exhaust gas heat from the main combustion engine as described in detail hereafter.
It is the object of this invention to transmit to the pumping piston of the power transmission apparatus the torque of the first crank shaft generated in the main combustion engine, which is separated from a power transmission apparatus to avoid abrupt rises in temperature.
It is another object of this invention to communicate the swash plate-type stirling engine with the exhaust gas outlet of the main combustion engine and to connect the one-stage screw-type compressor to the drive shaft of the swash plate-type stirling engine so that compressed air for operating the booster is produced, wherein the booster applies to the piston power transmission apparatus a relatively greater oil pressure.
It is another object of this invention to mount the crank shaft in an upper portion of the booster in order to smoothly operate the booster which exerts great oil pressure to the power transmission apparatus. It is another object of this invention to form a small orifice on a rod guide of the power piston to circulate the fluid oil, thereby giving a buffering action to the pumping piston rod during the operation of the engine system, wherein a pumping piston rod is connected to the pumping piston of the piston power transmission apparatus. It is another object of this invention to couple by means of the first crank shaft, the upper connecting rod of the combustion chamber piston mounted in the main combustion engine with a Y-type lower connecting rod of the pumping piston which drives the power transmission apparatus.
It is another object of this invention to operate the booster by the compressed air which is generated in the one stage screw-type compressor connected through the drive shaft of the swash plate-type stirling engine, using the exhaust gas heat, thereby forcing the booster to generate a greater force than is produced by the compressor alone, and to enhance net thermal efficiency by applying a relatively great oil pressure from the booster to the power piston of the power transmission apparatus which has a larger cross-sectional area than that of the combustion chamber piston or the pumping piston. As to this, an engine system in accordance with this invention is constructed as follows:
The engine body is provided with a main combustion engine for generating power and a power transmission apparatus for transmitting to the crank shaft a relatively larger power increased by the ratio of the cross-sectional areas between the combustion piston and power piston. The combustion engine and the power transmission apparatus are coupled together at their flanges by bolts.
The combustion chamber piston of the main combustion engine and the pumping piston of the power transmission apparatus are both coupled together with a first crank shaft of the main combustion engine by two connecting rods to have the same stroke distance. A swash plate-type stirling engine is mounted adjacent the exhaust gas outlet of the main combustion engine to operate by means of the exhaust gas heat from the combustion engine and to make the one-stage screw-type compressor, connected directly by a drive shaft to said stirling engine, generate compressed air.
A turbo charger is mounted adjacent the gas outlet to force a supply of fresh air into the combustion chamber of the main combustion engine. A booster is mounted between the compressed air source and the power transmission apparatus to amplify the air pressure derived from the compressed air source, and then to provide the amplified air pressure to the power transmission apparatus by operation of the cam in accordance with the rotation of the first crank shaft. An accumulator is assembled to communicate with the power transmission apparatus through the fluid oil pipe, thereby maintaining constant control of the oil pressure in the power transmission apparatus. Also, the booster for applying oil pressure to the external chamber of the power transmission apparatus in accordance with this invention is comprised of three portions; and upper portion receiving a crank shaft for smoothly operating the booster, a compressed air cylinder, in which a larger cross-sectional piston is mounted, and an oil cylinder, in which a smaller cross-sectional piston is mounted. Further, the main combustion engine in accordance with this invention is constructed so that the stroke distance of the combustion chamber piston is equal to that of the pumping piston of the power transmission apparatus. Namely, the upper connecting rod of the combustion chamber piston couples the two upper portions of the Y-shaped lower connecting rod of the pumping piston together with the first crank shaft mounted in the crank block of the combustion engine.